Complex, fractal structures are widespread in ecological systems and in some characteristic features of evolutionary processes. The origin of such patterns in terms of their dynamics is a challenging problem. A theory for these phenomena might have important implications in issues like the...

The dynamics of biological populations often appear quite complex, exhibiting considerable year-to-year variation in local abundances. One approach to dealing with ecological complexity is to reduce the system to one or a few species, for which meaningful equations can be written and even...

Using data drawn from large-scale databases, a number of interesting trends in the fossil record have been observed in recent years. These include the average decline in extinction rates throughout the Phanerozoic, the average increase in standing diversity, correlations between rates of...

Recently, it has been shown that the power spectrum of extinction intensity during the Phanerozoic takes a power-law form, which, it is suggested, may indicate the presence of critical phenomena in the dynamics underlying the extinction process. In this paper we reproduce these results using the...

A model of an evolving network of interacting molecular species is shown to exhibit repeated rounds of crashes in which several species get rapidly depopulated, followed by recoveries. The network inevitably self-organizes into an autocatalytic structure, which consists of an irreducible 'core'...

The causes of major and rapid transitions observed in biological macroevolution as well as in the evolution of social systems are a subject of much debate. Here we identify the proximate causes of crashes and recoveries that arise dynamically in a model system in which populations of (molecular)...

Life has existed on the Earth for more than three billion years. Until the Cambrian explosion about 540 million years ago however, it was restricted mostly to single-celled micro-organisms that were, for the most part, poorly preserved in the fossil record. From the Cambrian explosion onwards,...